Bouchard put on a dazzling display of foot movement and precision returns to throw Jankovic off her game. She blasted two aces and won 65 percent of her first-serve points in the 2 hour, 2 minute match at the Family Circle Tennis Center on Daniel Island in Charleston.

“She’s very solid,” Jankovic said of Bouchard. “She stays so low and takes your balls so early off the ground, so even if you hit hard, she just picks them up so easily and kind of directs them. That’s her biggest strength, that she can absorb someone’s ball and just use it.”

This is Bouchard’s second semi-final this year, after the Australian Open. She has had three wins over top-10 players prior to this, but never a No. 8. She beat world No. 9 Samantha Stosur in Charleston and then-10th-ranked Jankovic in Japan last year, and upset No. 10 Sara Errani at Indian Wells this year.

Bouchard has shot up the rankings over past year, going from No. 114 when she lost at Charleston to Jankovic last year, to 20th now.

Jankovic rallied in the second set after Bouchard broke the Serb to take a 4-3 lead, but the former world No. 1 then won four straight games to force a third set.

“I didn’t really think about how I was up a break in the second, because it was in the past and I had to move forward,” Bouchard said.

Jankovic, who won the Family Circle title in 2007, had one double fault and won just seven of 19 points on her second serve.